Advice on homeschooling my 17 year old.

Hello, I live in San Antonio, Tx. and my daughter is a junior in high school this year. She was diagnosed with
dyslexia in second grade and has been struggling ever since. I have been her advocate and have made sure that she always received the help she needed. This year has been the worst for her. Because of budget cuts to our district, my daughter was not able to get the help she needed and her teachers are so back logged trying to keep up with 30 students per class that my daughter is falling through the cracks. I want to home school her next year, however I don't know where to begin. Academically, she is not doing well and I know that I can help her at home. I would love some advice. Questions: 1. How do I let the school know that she will not be returning next year? 2. Would I need to submit some kind of lesson plan to the district? 3. Since she will be a senior, where would be the best place to go for lesson plans that follow my state curriculum?
Any advice would be greatly appreciated.